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Nov. 18, 2011 -- Most of us have had an occasional cold sore, but some people get the painful, unsightly sores over and over again. These cold sores, which tend to appear on or around the lips, are caused by herpes simplex virus type 1 (HSV-1).

Exactly why they occur more frequently in some people was not known, but now new research suggests some of us may have a genetic predisposition to frequent, severe cold sores.

The study is published in the Journal of Infectious Disease.

If the new findings are validated in other groups of people and researchers can zero in on exactly how a gene increases cold sore risk, new treatments won't be far behind, says study researcher John D. Kriesel, MD. He is an infectious disease specialist at the University of Utah School of Medicine in Salt Lake City.

Cold Sore Gene

Kriesel and colleagues narrowed down their search to one specific gene called C21orf91, which the researchers also call the cold sore susceptibility gene 1.

But "genes only account for 21% of susceptibility to cold sores, the rest of the risk is environmental," Kriesel says. Outbreak triggers may include sun, wind, trauma, or stress.

"This research may help us predict who is vulnerable to getting cold sores frequently. And the hope is that it will lead directly to new therapies," says infectious disease specialist Bruce Hirsch, MD.

"Anywhere from 50% to 100% of us have this virus and only a third get cold sores frequently. That is intriguing," he says. Hirsch is an attending physician at North Shore University Hospital in Manhasset, N.Y.

Keeping Cold Sores at Bay

"If we can identify a gene that can be modulated, it could go a long way to help these folks," says Richard J. Whitley, MD. He is a professor of pediatrics, microbiology, medicine, and neurosurgery at the University of Alabama at Birmingham.

Until new drugs are available, a little prevention goes a long way for people at risk of cold sores, he says.

"If you are out in the sun, put zinc oxide on the border where your lip and the skin of your face meet," Whitley says. Cold sores often develop along this area, which is called the vermilion border.

Dermatologist Michele Green, MD, looks forward to the day when there are new treatments she can offer people with frequent, severe cold sores. She works at Lenox Hill Hospital in New York City, and sees quite a few people who fit this bill.

"It can be really debilitating," she says. "Avoiding triggers such as sun and wind can also help prevent an outbreak."